The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
A piston for an internal combustion engine is a component that reciprocates in a cylinder with explosive force from expanding combustion gas in the cylinder to transfer rotational force to a crankshaft via a connecting rod. The piston for an internal combustion engine has an oil gallery formed therein. As oil circulates through the oil gallery, the piston may appropriately be cooled so that overheating of the piston may be prevented. The oil may be supplied by an oil jet to the inner wall surface of the cylinder and the oil gallery of the piston.
The oil gallery may have an inlet for receiving oil injected by the oil jet, and an outlet for discharging oil. However, the oil circulating in the oil gallery during the operation of the engine may be discharged through the outlet of the oil gallery before a sufficient cooling effect is produced. Since the outlet of the oil gallery is the farthest portion from the inlet of the oil gallery, it may be the most vulnerable in terms of the oil cooling effect
Meanwhile, as the piston moves up and down during the operation of the engine, the oil circulating in the oil gallery may be shaken along the axial direction of the piston inside the oil gallery. That is, oil shaking may occur.
However, we have discovered that the outlet of the oil gallery is open to the outside, so oil shaking does not occur at the outlet of the oil gallery. This may lead to the highest temperature on the top surface of the oil gallery facing the outlet of the oil gallery, resulting in reduced durability. Thus, there is a high probability of cracking in the top surface facing the outlet of the oil gallery, and such cracking of the piston may cause scuffing on the skirt of the piston.
The above information described in this background section is provided to assist in understanding the background of the inventive concept, and may include any technical concept which is not considered as the prior art that is already known to those skilled in the art.